DEV Community: Stefano Giraldi

Mount a Linux image on Windows and access to it from File Explorer with WSL2

Stefano Giraldi — Sat, 30 Oct 2021 10:28:46 +0000

Requisites

A Windows system with WSL2 and an installed distro.

1. Downlaod linux distro image

wget __linux_image_url

2. Run wsl console

$ wsl

3. Check disk image sectors

$ partx --show __linux_image_filepath__
NR  START     END SECTORS SIZE NAME UUID
 1   8192  532479  524288 256M      9730496b-01
 2 532480 3661823 3129344 1.5G      9730496b-02

3. Calculate offset

$ bc
bc 1.07.1
Copyright 1991-1994, 1997, 1998, 2000, 2004, 2006, 2008, 2012-2017 Free Software Foundation, Inc.
This is free software with ABSOLUTELY NO WARRANTY.
For details type `warranty'.
> 532480 * 512
> 272629760
> quit

4. Mount Image

Create mounting point

$ sudo mkdir /mnt/other

Mount image

$ sudo mount -v -o offset=272629760 -t ext4 /_path_to_file_image/__filename__.img /mnt/other
mount: /dev/loop0 mounted on /mnt/other.

Check mounted image

$ ls /mnt/other

5. Access to Filesystem through File Explorer

Open File Explorer
Type \\wsl$ in the address bar
Installed distros will be shown up. Click on it and navigate in the file system into the mounted path.

References

Photo Credit Dorolein

How to use Scoped Slot inside Vue's Render Function (Vuetify)

Stefano Giraldi — Wed, 05 Aug 2020 13:53:28 +0000

I tried to implement a custom component using Vue's render function. I get some problem to understand how to implement Scoped Slot inside a render function.

In this post, I will share the goal with the example code.

Beginning with the Template

This is the starting point. I had this simple Vue's template that I would convert into a custom component with the render function.

The reason is the classical one when is useful to use render function instead of the template: get more control of the rendering code of the custom component.

<v-tooltip bottom>
  <template v-slot:activator="{ on }">
    <v-icon color="primary" dark v-on="on">mdi-note</v-icon>
  </template>
  <span>Tooltip</span>
</v-tooltip>

Implementation with Vue's render function

This is the implementation with the render function.

const CustomIconTooltip = {
  name: "CustomIconTooltip",
  props: {
    tooltip: String,
  },
  render(createElement) {
      return createElement("v-tooltip", {
          attrs: { bottom: true },
          scopedSlots: {
            // Slot Name
            activator: ({on}) => {
              return createElement(
                "v-icon", { 
                  attrs: { color: "primary", dark: true },
                  on: on,
                },
                "mdi-note"
              );
            },
          },
        },
        this.tooltip
      );
  },
};

How to use CustomIconTooltip Component

<custom-icon-tooltip :tooltip="My Custom Icon Tooltip" />

Code Example

References

How to implement pagination with Oracle DB in a readability way

Stefano Giraldi — Mon, 01 Jul 2019 20:38:38 +0000

It was a Sunday morning. An early Sunday morning. I was waiting for my home wake up. So I looked again to my uncompleted task: how to paginate my recordset with Oracle DB (11c...).

I was inspiring to found a solution without using subselect.

I tried to avoid using subselect because I consider it not so readable (I found a lot of example with it). I've found my way using WITH statement.

The WITH statement permits to have a clean and simple SQL code.

This is the result.

WITH RECORDSET AS (
    -- put here your select with the complete recordset.
    SELECT FIELDA, FIELDB, FIELDC FROM TABLE
), 
NUMBERED AS (
    SELECT 
    ROW_NUMBER() OVER (ORDER BY FIELDA) RN, 
    RECORDSET.*
    FROM RECORDSET)
SELECT
    -- page number parameter
    :page_number PAGE_NUMBER, 
    -- total recordset pages
    CEIL((SELECT COUNT(*) FROM NUMBERED) / :page_size) TOTAL_PAGES, 
    -- page size parameter
    :page_size PAGE_SIZE, 
    -- total rows
    (SELECT COUNT(*) FROM NUMBERED) TOTAL_ROWS, 
    NUMBERED.*
FROM NUMBERED
WHERE 
    RN BETWEEN ((:page_size*:page_number)-:page_size+1) AND (:page_size*:page_number)

This code ask for two parameter: :page_size of your recordset and :page_number you want retrive.

The first fields contain pagination data: PAGE_NUMBER, TOTAL_ROWS, PAGE_SIZE and TOTAL_ROWS.

As well as I consider this a clean way to have a paginated recordset, I found it also very performing.